A systematic review of neuroimaging studies on psychedelics for major depressive disorder found that psilocybin, ayahuasca, and LSD alter brain activity and connectivity in ways linked to antidepressant response. Key changes include amygdala activity and functional connectivity alterations, shifts in medial and ventromedial prefrontal cortex connectivity, and decreased global brain network modularity. One ayahuasca study reported increased limbic activity. The evidence, based on only four datasets, suggests the default mode and limbic networks may be important targets for future research, but more data are needed to confirm these preliminary findings.
All participants reported decreased pain with ketamine infusions, though pain experiences varied. To improve ketamine's benefit for chronic neuropathic pain, it is important to address stigma, research ways to extend the duration of its effects, and provide a safe treatment environment. Understanding barriers and facilitators, along with implementing participant suggestions, can inform ketamine programs, improve access to pain management, and guide future research.